Potsdam is the capital and largest city of the German federal state of Brandenburg. It directly borders Berlin, and is part of the Berlin/Brandenburg Metropolitan Region. It lies on the River Havel 24 kilometres southwest of Berlin's city centre. Around the city is a series of interconnected lakes and cultural landmarks, in particular the parks and palaces of Sanssouci. Potsdam lay just outside West Berlin after the construction of the Berlin Wall. The Glienicker Bridge across the Havel connected the city to West Berlin and was the scene of some Cold War exchanges of spies. The Brandenburg Gate, on Luisenplatz in Potsdam, should not be confused with the gate of the same name in Berlin.